Switching apparatus for electric circuits



SWITCHING APPARATUS FOR ELECTRIC CIRCUITS Filed Decv 24, 1938 lINSULATION UNITED STATES PATENT OFFICE SWITCHING APPARATUS FOR ELECTRICCIRCUITS Carroll Stansbury, Wauwatosa, Wis., assignor to Cutler-Hammer,Inc., Milwaukee, Wis., a corporation of Delaware 9 Claims.

This invention relates to switching apparatus for electric circuits andwhile not limited thereto is particularly applicable to the control of aplurality of electric circuits such as condensers, which are to beprogressively connected in or disconnected from parallel circuitrelationship to each other.

An object of the invention is to provide an improved switch including aplurality of contacts, each connected to a separate circuit or device,whereby the contacts may be progressively connected in parallel with.each other to a common terminal.

Another object is to provide an improved switch of the aforementionedcharacter which is compact and which has a minimum number of parts.

Another object is to provide a condenser having a plurality of separatesections with a switch for connecting any desired number of suchsections progressively in parallel with each other.

Other objects and advantages will hereinafter appear.

In the accompanying drawing, Figure 1 is a side elevational view of aswitch embodying the invention and mounted on a condenser, and

Fig. 2 is a transverse cross section along the line 2-2 of Fig. 1.

Referring to the drawing, the condenser casing I is provided with anumber of parallel condenser sections (not shown) one pole of each ofwhich is preferably connected to a common terminal 2, while the otherpoles of the respective sections are connected to individual contacts 3arranged in a circle around a common center. The contacts are mounted onan insulating base plate, the inner face of which is represented by thedotted line 4, in Fig. 1, which in turn is suitably fastened to thecondenser casing I. A U- shaped bracket 5 is insulatedly mounted on thecondenser casing I. The bracket has a bearing G through which passes ashaft l, preferably of square cross section as shown, said shaft havinga reduced end 8 of circular form in transverse cross section, formingwith the main part a peripheral shoulder. A lever 9 fits over and isdriven by the square portion of shaft l and is held in place by a washerI D strung upon said shaft, the washer being provided with a circularopening II which fits the reduced end 8 of the shaft. The washer I I!thus holds the lever 9 against outward displacement from the squareportion of the shaft I and also forms an abutment between the peripheralshoulder on the shaft and the bracket 5. A stop pin I2 carried bybracket 5 cooperates with the lever 9 to limit the total extent ofangular rotation of the shaft l. A contact disc I3, preferably composedof phosphor bronze or similar resilient metal, comprises a series oflike sector-shaped arms I4 having a common center. Disc I3 is fittedonto shaft 1 to rotate therewith as shown in Fig. 2; and is normallybiased toward the contacts 3 by a coiled compression spring I5interposed between the disc I3 and the lever 9.

A relatively thin insulating plate or disc I6 of substantially annularform is positioned in a plane substantially parallel to the contacts 3.The disc I6 is held against rotation by engagement of the side walls ofthe peripheral notches I1 formed therein with the spaced parallel armsof the bracket 5. The disc I6 is further provided with a slot I8 (seeFig. 2) which permits passage of the arms I4 therethrough upon rotationof the shaft I. For this purpose the leading edge I9 of the slot is bentupwardly. Upon passing over the slot I8 the arms I4 lift the leadingedge of the insulating disc I 6, and on further rotation of the shaft 1they pass through the slot successively, thereby making contact with thecontacts 3 and connecting a lesser or greater number thereof in parallelrelation. Upon rotation of the shaft I in the opposite direction thearms I4 successively leave the contacts 3 and pass to the upper side ofthe insulating disc I6. The aforementioned action is facilitated byproviding a small knob or hemispherical boss 20 upon the under side ofeach of the arms I4 where they abut or engage the contacts 3. Thisraises their edges slightly above the plane of the contacts 3, so thatupon reverse rotation the arms I4 easily climb over the disc I6 toreinterpose it between the contact arms I4 and the contacts 3.

In the form of the device herein illustrated the arrangement is suchthat at least one of the segments I4 of the contact disc will at alltimes engage one of the contacts 3 (as shown in Fig. 2) so as to providea continuous circuit connection through at least one of the condensersections. Obviously, however, the width of stop lever 9 may be increasedto provide for engagement of tWo or more of the segments I4 with acorresponding number of the contacts 3; or the width of lever 9 may bedecreased to an extent sufficient to provide for movement of all of thesegments I4 from Iengagement with the contacts 3, whereby the circuitconnections through all of the condenser sections will be interrupted.

The reduced section 8 of the shaft 'I is provided 22. A dial 23 fastenedto the bracket 5 adjacent to the pointer 2l is graduated in an obviousmanner (not shown) to indicate the position of the contact disc I3relative to the contacts 3 and to thus indicate the number of condensersections in circuit.

The bracket 5 is clamped to the casing I by a pair of like straps 2l ofsemi-circular form attached to the arms of the bracket as by welding orbrazing, one of which straps may be provided with a terminal 25 for theconnection of the condenser into a circuit; the number of sections ofthe condenser included in parallel relation in such circuit depending,as aforestated, upon the relative rotary position of the operatingshaft. Straps 24 may be moved into or released from clamping positionrelatively to the condenser casing by adjustment of one or both sets ofbolts and nuts designated by the numerals 26 and 21, a strip or sheet offlexible insulating material 28 being interposed between straps 24 andcasing I.

As will be apparent from consideration of Fig` l, the condenser casing Imay be removed from bracket 5 by merely loosening one or both of thescrews 26. In order to permit such removal of the condenser casingwithout causing disassembly of the movable parts of the switchmechanism, I prefer to provide shaft I adjacent to the inner end thereofwith a shoulder to limit the degree 0f inward displacement of contactdisc I3, under the bias of spring I5, in the event that disc I3 ispositioned inwardly of the insulating disc IB. Said shoulder may be inthe form of a washer 29 insertable laterally with a press or snap fitinto an annular groove 'Ia provided adjacent to the inner end of shaft1.

It is obvious, that instead of rotating the contacts I4, the latter maybe held stationary, while the insulating disc I6 is rotated by theshaft 1. Other modifications will at once suggest themselves to thoseskilled in the art.

What I claim as new and desire to secure by Letters Patent is:

1. In a switching apparatus for electric cir- Puits, in combination, amultiplicity of stationary contact elements arranged symmetrically inthe form of a substantially complete circle and having the contactsurfaces thereof located in a common plane, a rotatable shaft locatedcentrally of said circle, a contact member comprising a substantiallycircular disc biased toward said contact surfaces and tending tocomplete circuit therewith respectively, an insulating disc positionedsubstantially parallel with the plane of said contact surfaces, saidinsulating disc being adapted to be interposed between certain of saidcontact surfaces and a variable portion of said Contact member uponrotary displacement of said insulating disc and said contact memberrelatively to each other in one direction, to interrupt circuit betweensaid contact member and the respective contact surfaces, said variableportion of said contact member being also adapted to be interposedbetween said contact surfaces and said insulating disc upon rotarydisplacement of said insulating disc and said contact member relativelyto each other in the reverse direction to complete circuit between thelatter and the respective contact surfaces, and said shaft being adaptedto effect such rotary displacement of said insulating disc and saidcontact member relatively to each other in each direction.

2. A circuit commutator comprising, a multitact surfaces arranged in theform of a substantially complete circle about a common center, a shafthaving its axis passing through said center at a right angle to theplane of said surfaces, a multiple-armed movable contact member also inthe form of a substantially complete circle attached to said shaft andbiased toward said surfaces and tending to complete circuit therewith,and an insulating disc mounted substantially parallel with the plane ofsaid surfaces and adapted to be interposed between the latter and thearms of said movable contact member progressively upon rotation 0f thelatter in one direction, the arms of said movable contact member beingalso adapted to be engaged with a gradually increasing number of saidsurfaces upon reverse rotation of said shaft, said arms being interposedbetween said insulating disc and said surfaces under the conditions lastmentioned.

3. A circuit commutator comprising, a multiplicity of contact buttonsarranged symmetrically in the form of a substantially complete circleand at equal angular displacements from each other and having coplanarcontact surfaces, a shaft having its axis passing through said center ata right angle to the plane of said surfaces, a plurality of normallycoplanar movable contact elements electrically connected with each otherand attached to said shaft at angular displacements from each otherequal to that of said contact surfaces and biased toward said surfacesto tend to complete circuit with said surfaces, and an insulating discmounted parallel with the plane of said surfaces and adapted to beinterposed between the latter and a progressively increasing number ofsaid movable contact elements upon corresponding rotation of the latterin one direction and to be interposed between a progressively decreasingnumber of said contact surfaces and said contact elements upon rotationof the latter in the opposite direction.

4. A circuit commutator comprising, a multiplicity of contact buttonshaving coplanar contact surfaces arranged in the form of a substantiallycomplete circle, a shaft having its aXis passing centrally through saidcircle at a right angle to the plane of said surfaces, a resilientcontact disc attached to said shaft and biased toward said severalsurfaces to tend to complete circuits therewith, and an annularinsulating disc mounted concentric to and parallel with the plane ofsaid surfaces and provided with a radial slot to permit said contactdisc upon rotation to pass through said slot so as to interpose saidinsulating disc between the contact disc and a progressively increasingnumber of said surfaces upon corresponding rotation of the contact discin one direction and to progressively decrease the number of saidsurfaces between which and said contact disc the insulating disc isinterposed upon rotation of the contact disc in the opposite direction.

5. A circuit commutator comprising, a multiplicity of contact buttonshaving coplanar contact surfaces arranged symmetrically in the form of asubstantially complete circle and at equal angular displacements fromeach other, a shaft having its axis passing centrally through saidcircle at a right angle to the plane of said surfaces, a resilientcontact disc provided with a plurality of radial slots to form sectorsthereof and attached to said shaft at angular displacements from eachother equal to that of said contact surfaces and blaseo. toward saluseveral surfaces to tend to complete circuit therewith, and an annularinsulating disc mounted concentric to and parallel with the plane ofsaid surfaces and provided with a radial slot to permit said sectorsupon rotation of said shaft to progressively pass through the slot insaid insulating disc so as to interpose the latter between said sectorsand said surfaces progressively, to thereby correspondingly decrease thenumber of lsurfaces in contact with said sectors upon rotation of saidshaft in one direction and to progressively increase the number ofsurfaces in contact with said sectors upon reverse rotation of saidshaft.

6. A circuit commutator comprising, an insulating block, a multiplicityof contact buttons provided with terminals and having coplanar contactsurfaces mounted in the form of a substantially complete circle on saidblock, a shaft in line with the center of said circle, a bearing bracketfor said shaft and connected to said block, a multiplicity ofelectrically connected radial resilient contacts also arranged in theform of a substantially complete circle and attached to said shaft androtatable thereby, common means to urge said contacts towards saidsurfaces to tend to make contact therewith, an annular flexibleinsulating disc mounted concentric to and parallel with the plane ofsaid surfaces and provided with a radial slot to permit said contactsupon rotation of said shaft to progressively pass through said slot soas to interpose the insulating disc between said contacts and saidsurfaces progressively and to correspondingly decrease the number ofsurfaces in contact with said contacts upon rotation of said shaft inone direction, and to progressively increase the number of surfaces incontact with said contacts upon reverse rotation of said shaft.

7. In a switching apparatus for electric circuits, in combination, amultiplicity of stationary contact elements arranged symmetrically inthe form of a substantially complete circle and having the contactsurfaces thereof located in a common plane, a manually rotatable shaftlocated centrally of said circle, a rotatable contactor comprising asubstantially circular resilient metal disc biased toward said contactsurfaces and normally tending to complete circuit with all of the samesimultaneously, a relatively thin insulating plate arranged in a fixedposition substantially parallel with and overlying said contactsurfaces, said insulating plate and said contactor being so formedrelatively to each other that upon rotary movement of said contactor inone direction from a given position thereof the same is adapted to rideover said insulating plate to effect disengagement of said contactorfrom certain of said contacts, said contactor upon subsequent rotarymovement thereof in the reverse direction being adapted to ride undersaid insulating plate to effect re-engagement of said contactor withsaid certain of said contacts, and said shaft having a positive drivingconnection with said contactor to effect rotary movement of the latterin either direction relatively to said insulating plate tnrougn an anglesubstantially greater than one hundred and eighty degrees.

8. A circuit commutator comprising, in combination, a multiplicity ofstationary Contact buttons having coplanar contact surfaces arrangedabout a common center in the form of a substantially complete circle, amanually rotatable shaft having its axis passing through said center atsubstantially a right angle to the plane of said Contact surfaces, arotatable contactor also in the form of a substantially complete circlewith which said shaft has a positive driving connection, said contactorbeing spring biased toward said contact surfaces and normally tending tocomplete a circuit connection with each of the latter, and a relativelythin approximately annular insulating plate non-rotatably mounted in aplane vsubstantially parallel to and overlying said contact surfaces,said contactor being adapted upon rotary movement thereof in onedirection to ride under said insulating plate into engagement withcertain or all of said contact surfaces, said contactor being thereafteradapted upon rotary movement thereof in the reverse direction to rideover said insulating plate out of engagement with said certain of saidcontacts, and means for limiting said shaft to rotation through an angleof less than three hundred and sixty degrees While providing forrotation thereof through an angle of substantially more than one hundredand eighty degrees.

9. A circuit commutator comprising, in combination, a multiplicity ofstationary contact buttons having coplanar contact surfaces arrangedabout a common center in the form of a substantially complete circle, amanually rotatable shaft having its axis passing through said center atsubstantially a right angle to the plane of said contact surfaces, arotatable contactor also in the form of a substantially complete circlewith which said shaft has a positive driving connection, said contactorbeing spring biased toward said contact surfaces and normally tending tocomplete a circuit connection with each of the latter, and a relativelythin approximately annular insulating plate non-rotatably mounted in aplane substantially parallel to and overlying said contact surfaces,said contactor being adapted upon rotary movement thereof in onedirection to ride under said insulating plate into engagement withcertain or all of said Contact surfaces, said contactor being thereafteradapted upon rotary movement thereof in the reverse direction to rideover said insulating plate out of engagement with said certain of saidcontacts, said insulating plate and said contactor being cooperativelyformed and arranged relatively to each other to insure engagement of thelatter with at least one of said contact surfaces in all rotarypositions of said contactor, and means for limiting said shaft torotation through an angle of less than three hundred and sixty degreeswhile providing for rotation thereof through an angle of substantiallymore than one hundred and eighty degrees.

CARROLL STANSBURY.

